How Terrazzo Works

Terrazzo Installation: The Pretty Part

Terrazzo, like the stuff found in the floors of St. Peter's Basilica, can be incredibly ornate and beautiful.
Terrazzo, like the stuff found in the floors of St. Peter's Basilica, can be incredibly ornate and beautiful.

Finally, the pretty part! The cement, cement matrix or epoxy is mixed on site, with colors added directly to the mix. Then the aggregate -- glass, marble, granite chips -- is mixed in. If you have lots of different colors, this means lots of different mixes. Epoxy cures quickly so it'll be done in smaller sections. The topping is spread evenly between the divider strips with trowels, or poured if it's a thinner aggregate. Next comes the curing. It could be less than a day, or several days in the case of traditional terrazzo.

Once the terrazzo is cured, you might be amazed at how, well, rustic it looks. Like lumpy concrete, actually. Go figure. You might like this look in some outdoor applications, and some people do leave their terrazzo this way. But that's probably not what you want to walk on in your house or office building. That's where grinding comes in. A huge grinding machine with disks covered in diamond or carborundum (silicon carbide) is run over the floor to expose the chips and create a smooth surface. Inevitably there will be some small holes left in the surface due to air pockets when the terrazzo was spread, so workers will go back and fill all of these in with grout. Then they apply a sealer to prevent any staining or moisture from getting in to the design.

Last comes polishing and waxing -- only then will you truly see the beauty of terrazzo. Now wasn't that worth the cost? But how much are we talking, you may ask? Using a cost estimator provided by the National Terrazzo and Mosaic Association, in my state it can cost between $10 and $16 per square foot. But terrazzo has what industry people call a "superior life cycle cost benefit." Although the initial install is pricey, you don't have to worry about replacing it or repairing it like you do with carpet, tile or just about any other type of flooring for at least 40 years. So enjoy. Or if you're like me, admire its beauty and durability anytime you walk across it.